(function(win,doc){
        //浏览器缩放时
        win.onresize=function(){
            change();
        };
        change();
        function change(){
            var oFs=doc.documentElement.clientWidth/(320/20);


            //设置根目录字体大小
            doc.documentElement.style.fontSize=oFs+'px';
        }
    })(window,document);